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Flashcards in Test 1 Deck (60):
1

Major branches of left coronary artery

LAD
- diagonal
- septal perforator
- intermediate

Circumflex
- obtuse marginal

2

Major branches of RCA

Acute marginal
PDA (in most)

3

3 most effective monitors to detect myocardial ischemia

ECG (detects ischemia 80% of the time)

PAC

TEE

4

2 factors which decrease myocardial oxygen supply and increase demand

Heart rate

Filling pressures (PCWP)

5

2 factors affecting coronary perfusion pressure

DBP (diastolic blood pressure)

LVEDP (Left ventricle end diastolic pressure)

6

Formula for coronary perfusion pressure

CPP = DBP - LVEDP

7

Role of HR management in optimizing myocardial oxygen supply and demand

LV fills during diastole

Total time in diastole key in perfusion

Modest increase in demand (HR) has major effect on supply

**as heart rate foes up, filling time goes down**

8

Hemodynamic variable most commonly associated with myocardial ischemia

Heart rate

9

Four factors that may adversely affect ventricular wall tension

Systolic BP

Afterload

LV filling volumes

Myocardial ischemia

10

Myocardial ischemia effect on wall tension

Changes compliance and will have higher pressures for same volume

11

Effect of IABP on myocardial oxygen supply

Augmentation of diastolic pressure resulting in increased coronary perfusion

12

Effect of IABP on myocardial oxygen demand

Reduction in afterload
-decreased cardiac work, oxygen consumption
- increased cardiac output
- decreased hemodynamic abnormalities associated with mechanical defects

13

Most commonly associated complication associated with CABG

A-Fib or rhythm disturbances

MI

Post op bleeding

Stroke

ARF

Post-perfusion syndrome (pump head)

Respiratory failure

Sternal wound infection

14

Predictors of morbidity/mortality with CABG

Age
Prior MI
MI location
Coagulopathies
CHF
Dysrhythmia
HTN
DM
PVD
cerebrovascular disease
Valvular heart disease
Smoking
Lung disease
ECG abnormalities

15

Time period most associated with morbidity mortality after MI

Within 1 month 35% have repeat MI

16

2 test measuring ventricular function in pt presenting for CABG

TEE

PAC

17

3 commonly used home meds in pt with CAD presenting for CABG

Beta blockers

Calcium channel blockers/ ACE inhibitors

Diuretics/thiazides

18

6 indications for placement of PAC

- LV dysfx
- angina w/i 48 hours
- symptomatic valve disease
- severe HTN w/ hx of angina
- large operation with anticipated intravascular volume changes
- vascular surgery with clamp of major arter

19

4 uses of PAC data during CABG

Measure CO

Detect, to, and trend myocardial ischemia

Measure and optimize ventricular preload and volume

Detect, treat, and trend valve dysfx

20

Clinical uses of intraoperative TEE during CABD

Ventricular function (EF, wall motion)

Wall motion abnormalities

Valve dysfunction

Stenosis or regurgitation

Chamber size may be indicative of dysrhythmia and dysfunction

21

Phenylephrine dose for CABG

30-60 mcg/min vs bolus

22

Dose for sedative hypnotics for CABG

Midazolam

Propofol

Etomidate

Midazolam 3-5 mg

Propofol 20-200mg

Etomidate. 10-20 mg

23

Opiod induction sequence dosage

Fentanyl

Sufentanil

Fentanyl 3-25 mcg/kg

Sufentanil 0.5-1.5 mcg/kg

24

Effect of fentanyl on volatile agent requirement

Dose of 25 mcg/kg, 50 mcg/kg, 75 mcg/kg, 100 mcg/kg

Increasing dosage of fentanyl results in decrease in MAC of volatile

25 mcg/GI = 40% decrease MAC

50 mcg/kg = 55% decrease MAC

75 mcg/kg = 65% decrease MAC

100 mcg/kg = 70% decrease MAC

25

With high dose fentanyl anesthesia resulting changes in hemodynamics

Vs inhalation anesthetic

Increase in HR, MAP, CI, MVO2

Inhalation results in decreased HR, CI, MVO2, MAP

26

Dose of epinephrine associated with extrasystoles when using Isoflurane

7 mcg/kg

27

6 causes of Myocardial ischemia during anesthesia

- coronary artery occlusion
- tachycardia
- high PCWP/CVP (>12-15)
- hypotension
- severe hypertension
- increased workload or high CO (sepsis)

28

6 signs of myocardial ischemia

- ST segment abnormality
- dysrhythmia
- conduction abnormality
- PA waveform abnormality
- decreased myocardial performance (low CI or BP)
- wall motion abnormality( echo, visual)

29

Intervention of Nitrates for myocardial ischemia

Decreases wall tension better than anything else

30

Intervention of beta blockers for myocardial ischemia

Decreased contractility and HR

**use esmolol not metoprolol**

31

Intervention of calcium channel blocker drugs for myocardial ischemia

Just drop BP

Not helpful with anything else

32

5 patient subgroups requiring higher perfusion pressures

- Acute MI/ongoing ischemia
- renal/cerebral insufficiency
- Left main/left main equivalent
- aortic stenosis
- chronic hypertension

33

4 potential sources of conduit for bypass grafts for CABG

- LIMA
- RIMA
- radial
- saphenous veins
- gastroepiploic

34

Blood pressure maintenance during arterial cannulation

Maintain SBP <100

**if higher can dissect aorta**

35

6 sources of rhythm disturbances associated with surgical manipulation CPB

- atrial cannulation/vent stitch
- RFG catheter (retrograde cardioplegia)
- pericardiotomy
- lap under heart to explore distal
- myocardial ischemia
- dissecting out heart for redo/pericarditis

36

Heparin dose in prep for CPB

Goal ACT after periocardiotomy and prior to aortic cannulation

300 units/kg

Goal ACT >400 second

37

Hemodynamic consequences of “mixing” or “RAPing”

Decreases viscosity and circulating norepinephrine levels

**decreases SVR**

38

4 goals of cardiopulmonary bypass

- oxygenation of blood and elimination of carbon dioxide (ventilation)

- circulation of the blood

- systemic cooling and rewarding

- diversion of blood from heart to provide bloodless surgical field

39

Cross clamp strategies for distal anastomoses

Distals done with cross clamp on

Mammary done last to avoid twisting IMA

40

Cross clamp strategy for proximal anastomoses

Cross clamp removed, partial clamp of aorta for proximal

At risk for ischemia until proximal completed

41

Protamine dosing after separation of CPB

10mg test dose after satisfied with heart performance

Then 25 mg every minute

Typical dose 250 mg

**remove aortic cannula with 1/2 protamine dose is in***

42

On CPB blood pressure is

Flow X SVR

43

To reduce flow and separate from CPB (hemodynamics)

SVR is increased

44

Prior to CPB what should you do with PAC

Pull PAC back 2 cm bc easier to perf RA when volume lost to go on CPB

45

Law relating to wall tension

LaPlace’s Law

46

Difference in collateral flow and natural flow r/t perfusion of heart

Collateral flow doesn’t reach subendocardial as well as epicardial

47

5 advantages of OPCAB

Less neuropsychological impairments

Fewer inotrope, dysrhythmia postop

Improved hemostasis

Less need for transfusion and fluids

Less postop renal insufficiency

48

6 pt subgroups most likely to benefit from OPCAB

>70 yrs old
Low EF
Redo CABG
Significant comorbidities
Calcified aorta
Pt refusing blood products

49

Role of intracoronary shunts for distal anastomoses

Placed after arteriotomy

Decreased bleeding

CBF maintained though reduced

50

4 methods of display ante of heart for distal anastamosis

Laps
Towel
Deep pericardial sutures
Suction stabilizer devices

51

Effects of displacement on
CO/SV and BP

Decreased RV filling but elevated filling pressures rt RA compression

Decreased RV output = underfilled LV = lower SV/CO

Decreased CO = decreased BP

52

Effects of displacement on valve function

Vertical position = distortion of MV and TV

Significant regurgitation

53

Myocardial ischemia manifestations during OPCAB

Elevated PA **
Deterioration in heart performance

ST elevation

New RWMA

54

Target vessel positioning associated with biggest decrease in SV and increase in CVP

Circumflex positioning

55

4 strategies to manage Herat rhythm disturbances during OPCAB

Lidocaine (esp RCA)
Magnesium 2gm (keep K4.0)
Nitro during distal anastamosis for spasm

56

Heaprin dose

ACT goal

1.5-2mg/kg (usually 10,000-15,000 units)
—1/2 full CBP dose)

3000 units if vein taken prior to bolus for revascularization

Keep ACT >250

57

Usefulness of TEE monitoring

RWMA

CI superior to TEE with displacement

58

Order of grafting

Colalteralized
LAD w. LIMA
Proximal before distal
Diagonals
RCA
PDA
Circ
2nd and 3rd OM
PLA
OM
Ramus intermediate

59

Inferior wall exposure surgical maneuver fo limit hemodynamic compromise

Table flat and retraction sutures relaxed

Decreases compression of RA/RV

60

Surgical maneuvers to manage hemodynamic changes

- Order of grafts based on hemodynamic consequences
- OR graft most diseased first
-close communication with anesth
- DPS to bring great vessels and chambers into same plane
- open R pleura for lat grafts to avoid compression
- lift R sternum to make more space
(Towel under R side of retractor)
- remove pleurocardial fat